this time to jennifer hudson's rendition of the al green song "let's stay together." you were really getting into it. >> i saw barack dip a little bit. michelle looked gorgeous in her ruby gown. she picked jason wu a second time. his career is now set. >> wu and chu tonight. >> the dance kicked off the real party tonight. last night was all about the bling. here's abc's cecilia vega. >> reporter: it was their first dance the second time around. ♪ happy or sad there were only two official balls this year, practically austere by inaugural standards. but the obamas proved they still know how to throw a party. ♪ obama's on fire >> reporter: alicia keys and stevie wonder played to a crowd of thousands. donors and devotees decked out in black tie and a whole lot of sparkle. but the celebrities ceded the spotlight for the real stars of the night, the president and the first lady. and while the day was all about barack obama -- >> some may dispute the quality of the president, but nobody disputes the quality of the first lady. >> reporter: tonight was all about michelle.